Industrial Noise & Vibration Centre

+44 1753 698 800

Case Studies

An elegant engineering solution to your noise or vibration problem may already be available. Search below the largest database of source control case studies in the world for alternatives to conventional, high-cost palliatives such as acoustic enclosures, silencers, barriers etc.

Showing 31 to 45 out of 94
  • nuisance
  • fan noise attenuation
  • noise control
  • environmental noise

Lifting a Fan Noise Abatement Notice

lifting fan noise abatement notice

Approaching £50000 had been spent on silencing two large, roof mounted fans in an attempt to satisfy local complainants and the Environment Agency authorities – unfortunately without any success due to a lack of diagnosis of the cause of the noise problem. When the company approached us to provide them with a solution, we asked them to email us a couple of video clips of the fans.

Our initial diagnostic analysis of the video sound-tracks showed that the noise issue was caused by the interaction between the blade pass tones of the 2 similar fans that caused "beating" - modulation of the tonal level that adds to the subjective nuisance. This allowed us to design our unique Quiet Fan technology aerodynamic inserts to reduce the noise by over 20dB at source without enclosures, silencers or lagging – permanently and without maintenance. This was achieved with minimal down-time and at a tiny fraction of the cost of conventional alternatives. Read more on fan noise control without attenuators.

  • nuisance
  • noise control
  • fans
  • environmental noise
  • extract system

Fume Extract Fan Noise Control

extract system low frequency noise attenuation

Fume or dust extract fan noise is a very common cause of noise complaints and can also be an occupational noise hazard. Conventional extract fan silencing is not only subject to clogging, but can also increase backpressure, reducing system efficiency - not what you need from these systems.

A large weld booth fume extract fan system generated high-level low-frequency tones at 35Hz and harmonics that caused extensive complaints in nearby offices. Diagnostic measurements proved that the major problem was an in-duct standing wave resonance in the manifold that was amplified by panel resonances in the filter enclosure. The elegant solution was to insert an air-guide plate into the ductwork to reduce turbulence, fitting an acoustic absorbent plug into an end cap to create an anechoic termination and applying stiffening ribs to detune the noise radiating panels.

These measures were fitted within a day at very low cost, not only eliminating the low-frequency tones (30dB reduction), but also dramatically improving the fume extract fan efficiency and hence reducing running costs.

  • chiller fan
  • environmental noise
  • fan noise attenuation

Data Centre Server Chiller Farm – £100k wasted on noise control

data center server farm fan noise attenuation

Data centres require a lot of cooling - which involves noisy chiller fans, air handling units and condensers. Moreover, in addition to the general fan air noise, there are often low-frequency tonal elements (hums) that cannot be silenced using conventional silencers and acoustic barriers. Fortunately, there are low-cost alternatives...

An Abatement Notice was issued re the noise from a large array of chillers and air handling units at this data centre. The company had already spent nearly £100k on noise control with very little success and were considering claiming Best Practicable means (BPM) in court when the council suggested they might like to get a second opinion from us…

Our accurate diagnosis and control technology meant that we could guarantee BPM would be implemented by recommending a range of innovative noise reduction techniques for the AHUs and chiller condenser fans. These reduced the plant noise by 15dB at less than half the previously expected cost. If this approach had been implemented in the first place, the company would have saved over £100k, the council would have saved resources and the complainants would not have had to suffer unnecessary disturbance over a 2 year period.

More on data center, chiller, condenser and heat exchanger fan noise reduction.

  • nuisance
  • planning
  • noise control
  • environmental noise

Brown Field Site Development – noise control makes 200 houses possible

Noise reduction allows site planning permission

High levels of environmental noise from nearby industrial premises affecting over 18 acres of mixed brown-field and farmland had caused the planners to assess the site as unsuitable for housing. However, as the City Council was aware of our expertise in industrial and fan noise control and they suggested that the Planning Consultants contact us for a second opinion to see if there was a solution.

The developers then paid for us to both evaluate the noise control options and to design permanent solutions (including our Quiet Fan noise control technology for the problem fans) that could be implemented at each of the 4 companies involved. The companies themselves were extremely happy with the process as they had all had previous noise complaints that were now resolved. Moreover, the noise mitigation measures permanently eliminated the environmental noise problem which allowed the "planning blight" to be lifted. Consequently, planning consent was granted for 200 properties to be built on a site previously considered too noisy for housing (making it now worth £millions) at a cost to the developers of less than £45k.

  • vibration control
  • nuisance
  • noise control
  • environmental noise

Tunnel Boring – low frequency noise and vibration control

tunnel boring vibratory sieve noise reduction

Local residents were complaining about low frequency noise and vibration from a large tunnel operation which also exceeded the overall planning consent noise levels. The low frequency noise and vibration was generated by the spoil processing vibratory sieves and the previously proposed remedial measures included a deep ditch and a very large barrier. Neither of these would have been effective...

Our detailed diagnosis showed that the main problem was caused by excitation of some of the steel building wall and roof panels that then radiated the vibration very efficiently as noise. The panels we had identified as a problem were de-tuned quickly and cheaply by introducing stiffening ribs. This reduced the 15Hz noise radiation by 8dB which was sufficient to prevent further complaints.

  • power press
  • nuisance
  • noise control
  • environmental noise

Power Press Shop – impulsive noise problems

power press noise reduction

Complaints about press noise from a factory unit had resulted in an Abatement Notice from the Local Authority. After the company had spent over £12000 on the building to no avail and with another £65000 expenditure planned as recommended by noise consultants (but without any guarantee that it would solve the problem), they had decided to challenge the notice in court.

However, as our Best Practicable Means (BPM) Noise Control Audit for the Local Authority proved that the best solution was to treat the small number of power presses that were causing the issue at source at a fraction of the cost of legal fees, this approach was adopted by the company. The engineering source control measures reduced the low frequency noise components by 9dB - 24dB, eliminating further complaints. This is a classic case where consultants have not carried out detailed diagnostic work to identify the precise causes of complaints, who do not have the engineering skills needed to design source control modifications and are therefore limited to recommending conventional palliatives that are not best practice at a very high cost to the client, the LA and to the disturbed residents.

  • nuisance
  • planning
  • noise control
  • environmental noise

Combined Heat and Power Station Planning and Noise Reduction

A new CHP installation on a large industrial site next to a housing estate was subject to very stringent planning constraints with respect to noise. A full impact assessment was made and, in conjunction with both the supplier and the Local Authority, a detailed noise specification drawn-up for all components of the installation.

We not only produced the noise specifications, but also provided detailed engineering noise control measures for the CHP installation project. An innovative approach was used to cut the expected cost of the overall noise control measures to meet the noise specification by approaching 90% by developing low cost engineering modifications to reduce the noise from other contributory sources on the site (fans, compressors, pumps, gas mains...) at the nearest dwellings by 8dB(A). This meant that the stringent noise attenuation requirements for the CHP installation could be significantly relaxed to generate very substantial cost savings.

  • nuisance
  • noise control
  • environmental noise
  • burner
  • combustion
  • boiler

Dual Fuel Burner Noise Reduction – natural yoghurt based control!

burner combustion head noise control

The cause of complaints about environmental noise levels was traced to this dual fuel burner on a Heinz site. The company contacted us to assess the noise control options as the conventional palliative noise control techniques for this sort of problem involve fitting large silencers into the stack and converting the boiler house into an acoustic enclosure – eye-wateringly expensive with extensive down-time (which would have caused serious production problems).

The source was diagnosed as a 116Hz low frequency “drone” – a very common type of burner noise control problem – with a stunning simple alternative solution that comprised a set of aerodynamic modifications that fitted inside the combustion head. The initial trials were conducted using an adapted yoghurt pot fitted inside the burner head – as far as we know, this is the only known yoghurt-based noise control application… The modified pot reduced the drone by 16dB, completely eliminating the problem. The cost? Less than £2k with a down-time of a few hours (aluminium version of the yoghurt pot). This new approach and technology can be an incredibly cost effective solution to many burner or combustion noise problems.

  • nuisance
  • planning
  • noise control
  • environmental noise

Quarry Noise Attenuation - planning and execution

quarry planning noise management

A detailed environmental noise impact assessment established 24 hour target noise levels for a new quarry as part of the planning submission. This was supported by predictions of the changes in the local noise environment throughout the working life of the quarrying project and a detailed compliance verification procedure.

Detailed Buy Quiet noise purchasing specifications were provided for every piece of plant to be installed within the quarry. These included the measurement procedures and the best practice noise control measures that should be used by the suppliers to ensure that the target noise levels were met as cost effectively as possible (most suppliers have very little knowledge of noise control engineering technologies).

  • nuisance
  • noise control
  • impact noise
  • environmental noise
  • recycling

Scrap Recycling Impact Noise Control

scrap recycling yard impact noise control

£250 000 cost saving on environmental noise control…

Everyone knows that massive noise barriers are the only solution for noise from scrap yards and recycling centres. Everyone knows wrong...

We saved a scrap recycling company over £250 000 on the proposed noise barriers by controlling the dominant scrap impact noise at source. This is new technology that can reduce the impact noise from crushers in quarries, dump trucks, shredders, trains, manual handling etc by up to 15dB(A). Compared with conventional noise control techniques, the cost is miniscule, it is incredibly rugged, can be fitted very quickly and has no effect on plant operation, maintenance or access.

  • damping
  • noise control
  • petrochemical
  • environmental noise

Power Station Gas Facility – high damping noise reduction

Gas pipeline acoustic lagging noise control

Noise levels from a power station were uncomfortably close to their environmental noise planning conditions. Detailed diagnosis proved that the dominant contribution was high-frequency noise (>500Hz) radiated by the Gas Reception Facility. Vibration measurements narrowed-down the source to the reducer, expander and associated valve section of the facility.

Sound Damped Steel was brought in to fabricate our innovative, high-performance acoustic lagging. This has an outer skin constructed from highly damped laminated steel, making it very tolerant of installation practicalities. Moreover, options are available that eliminate the corrosion problems inherent in conventional lagging designs. The diagnostic process illustrates how costs can be kept to an absolute minimum by precisely ranking noise contributions from different components, even amidst complex arrays of pipework, valves and other sources. The effect of the treatment was to reduce the noise from this source by 16 -19dB(A), eliminating it as a contributor off-site. Occupational noise levels in the area were also reduced by an average of 8dB(A). More information is available on the Sound Damped Steel installer website here.

  • infrastructure
  • rail
  • noise control
  • environmental noise

Edgware Road Station – nighttime track maintenance noise

Edgware road station noise complaint reduction

From regular noise complaints to less than zero complaints…

As the station is overlooked by apartments, nighttime noise from underground track maintenance activities had given rise to regular complaints from local residents. The contractor, Balfour Beatty, decided to be proactive by asking us to introduce our new Acoustic Camouflage technology.

This solution involved relocating welfare facilities to take advantage of existing site screening features coupled with temporary acoustic barriers – not just for the facilities, but also for the vehicles and workforce at the station entrance. Then a pair of Acoustic Camouflage systems were installed at the station entrance and near the welfare area to dispense non-directional, shaped signature background noise. Despite raising the background noise by 8dB(A) at key locations, it was subjectively inaudible on the other side of the street. As a result, these systems were very successful at camouflaging the key annoying elements in the noise from the site activities.

The end result was not just to reduce the number of complaints to zero, but congratulatory emails were received from previous complainants complimenting the company on the effectiveness of their noise management...

  • buy quiet
  • fans

Plant Noise Information – the lack of frequency data from suppliers…

Fan tonal noise waterfall analysis

The most compromising and common issue we encounter is that plant noise data (fans in particular) never includes frequency signatures. Octave bands: yes. Narrow band (that defines if there is a tone): no. If there is a tone, in the UK it attracts a 6dB penalty – which only puts your predictions out by a factor of x4! Consequently, if you want to play safe, you over-engineer mitigation which adds a massive cost overhead. This is unacceptable. We try to get round this by asking for a smartphone recording from an installation anywhere in the world so we can design the optimum noise control measures.

This is a ridiculous state of affairs considering that you can do an accurate narrow band tonal analysis with a smartphone app for free. Noise consultants are also to blame as only a very small proportion of them carry out tonal analyses.

  • damping
  • pump
  • noise control

Power Station 600hp Water Pump Noise Reduction

Power station water pump noise control

These water pumps generated 95 – 99 dB(A) and were the subject of a dispute with the suppliers re the agreed noise levels. Various acoustic barriers and partial enclosures were being considered – at high cost and with considerable access issues. Our detailed vibration analysis proved that the required noise reduction could be achieved simply via constrained layer damping plus laminated close shields. These provided a 12dB(A) noise reduction with no effect on access, operation or maintenance – and at a tiny fraction of the previously proposed costs.

This is an example of the efficacy of accurate diagnosis coupled with good engineering and knowledge of materials. More information is available on the Sound Damped Steel installer website here.

  • damping
  • noise control
  • machining

Alternator Casting Machining Noise Reduction

Alternator end shield casting machining noise control

Machining of alternator end castings produced 104 dB(A) at the operator, dominated by a “squeal” radiating from the casting. Overlapping hanging strips had been fitted round each machine in an attempt to reduce noise – but in every case they had been cut down at the operator location to improve access. Frequency analysis showed the dominant tones were excited by cutting forces with evidence of chatter-marks on some of the machined surfaces. We designed a low cost damper to reduce the casting vibration.

This reduced “squeal” tone by 32 dB and the overall noise level by 16 dB(A) at source, improved the quality of cut and reduced the machining cycle time to improve productivity.

Showing 31 to 45 out of 94